enhanced multi user support is activated. Keeps popping up randomly

Hello - so I have a weird issue - one of my users is randomly getting the Multi User Support pop up with nothing else that says:

"Enhanced multi user support is activated. please click here for further information"

There was no Teamviewer even downloaded onto their computer strangely enough.

It keeps happening now, even with Teamviewer 13 downloaded onto their system.... they get just the pop up with text in the middle of their screen. So how it looks below is exactly how it looks on their screen with no other background. Once you click it - regardless of how it dissapears shortly.... anyone know how to solve this issue?